It's the highest-profile showdown yet between these coaches and their teams, clearly now the premier franchises in the NFC, if not the entire NFL.

What's the deal between Carroll and Harbaugh?

To coin a term used by Seahawks cornerback Richard Sherman to describe the Seahawks-Niners rivalry in general, there is no love lost and no love found between them. They're not friends. And no one is saying they are.

But neither, it seems, is there any raging hatred or fixation that consumes either man, as has been suggested since 2009.

That's when they were arch-rival head coaches at the college level, in the then Pac-10 conference -- Carroll at Southern Cal and Harbaugh at Stanford.

There was that one famous incident everyone always refers to, in '09.

To set it up, when Harbaugh took over the Cardinal in 2007 they were awful. Pac-10 cellar dwellers. And Carroll's Trojans, of course, were established then as the most powerful program in the country, let alone in the Pac-10.

"We have not been friends over the years because we don't know each other very well," Carroll said. "Just know each other through the game, when we used to coach against him back when he was playing, and since we've coached against each other.

"So it's a very confined relationship in that regard. For whatever reason, you guys have had a field day with thinking that it's something other than it is.

"I have great respect for what Jim has done and I think he's a tremendous football coach. I don't know him very well personally. So that's it. That's where it starts and stops and all the rest of the stuff, you've guys have had a blast with it, but there's nothing there."

Harbaugh this week has been asked about The Feud, too, of course, and he said far less. As is his wont. But he essentially agreed with Carroll.

"I haven't seen where that's really even talked about anymore," Harbaugh said. "And it would be as irrelevant now as it would have been then, when people made a bigger deal out of it.

"So, irrelevant. Irrelevant."

Asked what Carroll brings to the Seahawks, Harbaugh talked at length. That's rare for him at any news conference.

Then he listed off Carroll's accomplishments, including: "How well they're coached. What a great job their organization does. The competitiveness of their players. Execution, consistently, really -- really good week after week.

"And it's hard to get to this point "¦ They did it better than anybody did it his entire season."

Niners centre Jonathan Goodwin told me Wednesday that in three years in San Francisco he has never heard Harbaugh say a negative thing about Carroll.

"I mean, from a media standpoint you would think so, from all the attention it gets, the history there," Goodwin said. "But you just never hear coach Harbaugh bash coach Carroll."

In their current jobs, Harbaugh is 4-2 against Carroll. But Seattle has won two of the past three and outscored San Francisco 71-16 in those two victories at CenturyLink Field.